python.tmpl

{{define "main" -}}
"""Code generated by tools/codegen from model.json; DO NOT EDIT.

Generated form: a scheduler loop over transitions whose arcs have been unrolled
into straight-line conditionals. Nothing walks an arrow list at runtime.
See FORMS.md.
"""


def initial_marking():
    """The marking is a set of marked place names. The net is 1-safe."""
    return { {{- quoteAll .Initial -}} }


def render(marking):
    """Canonical trace rendering: marked places, sorted, comma-joined."""
    return ",".join(sorted(marking))

{{range .Transitions}}
def fire_{{snake .Name}}(marking):
    """Check enablement, then apply.

    Every check precedes every mutation, so a disabled transition leaves the
    marking untouched.
    """
{{- range .Inputs}}
    if "{{.}}" not in marking:
        return False
{{- end}}
{{- range .Guards}}
    if "{{.}}" not in marking:  # guard
        return False
{{- end}}
{{- range .Blockers}}
    if "{{.}}" in marking:  # inhibitor
        return False
{{- end}}
{{- range .Outputs}}
    if "{{.}}" in marking:
        return False
{{- end}}
{{- range .Inputs}}
    marking.discard("{{.}}")
{{- end}}
{{- range .Outputs}}
    marking.add("{{.}}")
{{- end}}
    return True

{{end}}
# Sorted transition order — deterministic, and not necessarily the order the
# interpreter form declares.
SCHEDULE = [
{{- range .Transitions}}
    ("{{.Name}}", fire_{{snake .Name}}),
{{- end}}
]


def main():
    marking = initial_marking()
    step = 0
    while True:
        fired = False
        for name, fire in SCHEDULE:
            if fire(marking):
                step += 1
                print(f"Step #{step}: {name} => {render(marking)}")
                fired = True
                break
        if not fired:
            return


if __name__ == "__main__":
    main()
{{end}}